Preparation and repair of metal or metallic components, such as turbine blades and turbine buckets, can be done through welding and/or brazing. Components having a titanium aluminide (TiAl) surface can be welded or brazed. However, the welding or brazing can adversely affect the microstructure and/or mechanical properties of the component. For example, welding or brazing can form a heat affected zone that results in debit of mechanical properties.
TiAl can offer benefits of high strength to weight ratio and good resistance to temperature oxidation. However, certain processing of TiAl can form microstructures that are undesirable. For example, heating and hot working of TiAl above temperatures of 1150° C. can result in a duplex structure including equiaxed grains and gamma/alpha2 lamellae within a polycrystalline lamellar structure of an article formed from melting and casting of the polycrystalline lamellar structure. This change in microstructure due to hot working is generally undesirable and the lack of refined gamma/alpha2 lamellae results in decreased strength and/or shorter fatigue life and creep life.
An article with a TiAl surface and a TiAl application process not suffering from one or more of the above drawbacks would be desirable in the art.